The present invention relates primarily to a filter assembly adapted to filter rainwater flowing from a downpipe into an underground pipe, leading usually to a soakaway.
Guttering systems, in the UK for example, consist of lengths of gutter attached to fascia boards, which then connect to downpipes. These in turn carry the water from the gutter to ground level.
All water from the downpipes should desirably lead to soakaways, such as are specified by UK Building Regulations, and not into foul drains or cesspits. It enters the soakaway by one of two methods.
1. A small percentage have a downpipe terminating above a gully with a grille on top which is part of an underground system leading to a soakaway which would have been installed when the house was built. This grille collects large debris which is easy to clear away but allows silt and small debris to enter the pipes leading to the soakaway which often eventually clogs/silts the system up completely. To repair this damage they have to be re-dug and re-piped. This system is superior to the following as it does have a grille to stop the large debris and does not become blocked as quickly as option 2.
2. The larger percentage of downpipes currently in use terminate directly into the clay or PVC underground pipe system leading to the soakaway. This means ALL debris and silt enters the underground pipe work, Therefore it all ends up in the underground pipe work and/or the soakaway often eventually clogging/silting the system up completely. To repair this damage they have to be re-dug and re-piped. Sometimes pipework can be cleared by hand-operated devices or by pressure devices, but it is time-consuming and can be expensive. Also, the downpipe needs to be removed and then replaced afterwards.
The only products on the market at present which are aimed at reducing these problems are not very effective. A mesh is available which fits on top of the gutter but this is not very attractive or effective as they do not fit very well and look unsightly. A plastic/wire mesh xe2x80x98balloonxe2x80x99 is available which fits in to the top of the downpipe in the running outlet. However, such balloons block very quickly, especially when rain falls after a long dry spell. The rain takes a lot of debris in a short space of time and is collected around the balloon which in turn becomes blocked up and the rain overflows over the top of the gutter. These need to be constantly cleared out which can he very awkward for a lot of people.
According to one aspect of the present invention a rainwater filter assembly comprises a rainwater filter means comprising a housing and a filter assembly, said housing comprising an inlet for receiving rainwater discharging from a downpipe, an outlet for connection in series with an underground pipework, and housing walls defining a silt collection chamber in the flow path between said inlet and said outlet, whereby silt settles in said silt collection chamber from rainwater passing from said inlet to said outlet, said housing walls comprising a silt collection chamber base, and said filter means being supported by said housing for filtering coarser material than silt from rainwater which passes from said inlet to said outlet, said outlet comprising an outlet entrance positioned higher than said base, for allowing rainwater to pass from said silt collection chamber to said outlet.
Thus the filter assembly is capable of filtering coarse material from the water and provides a silt collection chamber so as to reduce the quantity of particulate material that passes to the pipework in the ground and to the soakaway normally connected to such pipework.
Preferably the assembly is provided with a downwardly projecting tubular outlet. The tubular outlet may be connected to a pipe in the ground.
The assembly may be provided with locating means which is operative to ensure that the outlet is positioned so as to discharge into the underground pipework.
The locating means may be provided with an aperture, the aperture being suitably sized so as to receive the tubular outlet.
The tubular outlet is preferably sized to be received within the upper end of a residual piece of downpipe that is left after removal of a short portion of the existing downpipe just above the ground. Downpipes come in a range of standard sizes, and some are round and others square, but a tubular outlet of typically 56 mm outside diameter can be received within most such pipes.
Downpipes are typically made of cast iron, aluminium, asbestos or PVC and are generally secured in an underground pipe collar with mortar, and this joint is best left intact, so the ability of a 56 mm tubular outlet to fit most existing downpipes is advantageous.
When the filter assembly is to be fitted to an existing installation in which a downpipe connects at ground level with an underground pipe leading to a soakaway, a portion of the downpipe is removed by cutting through the downpipe, at or adjacent to ground level, preferably leaving a short section of downpipe connected to the underground pipework. The filter assembly can then be mounted in position by cutting the tubular outlet to size and inserting the tubular outlet of the assembly into the short remaining section of downpipe.
Advantageously an O-ring may be fitted between the outlet and the remaining portion of downpipe to provide a snug fit, even when the downpipe is of square section.
The filter means preferably comprises first and second filters positioned in series with each other in the flow path of at least the bulk of water flowing from the inlet to the outlet.
The first filter is preferably in the form of a relatively coarse grating which preferably extends across substantially the full width of the upper end of the housing which is otherwise substantially open.
The downpipe which discharges into the upper end of the filter housing may be provided with a downpipe shoe, or the lower end of the downpipe may be cut at an angle, to produce a controlled discharge of water onto the first filter.
The second filter is preferably in the form of a relatively fine grating sized to collect floating debris which is of intermediate size to that of silt particles and large particulate debris such as leaves, moss and twigs which will be collected by the first filter.
The apertures in the second filter are preferably sized to collect small floating debris such as beech mast or blossom.
A guard is preferably provided to prevent water discharging from the downpipe from impinging directly on the entrance to the tubular outlet.
The guard is preferably in the form of a plate integral with the first filter so as to form an unapertured portion of the first filter.
The second filter is preferably located at or adjacent to the entrance to the tubular outlet, which it will be recalled is above the base of the silt collection chamber. Water will overflow from the silt collection chamber into the tubular outlet, so that any fine floating debris will tend to be at about the level of said entrance, and locating the second filter in this region is advantageous.
The second filter is preferably a grid of substantially dome shape which is adapted to extend over the outlet entrance.
Bypass means is preferably provided to enable some of the water flowing from the silt collection chamber to pass to the outlet entrance without passing through the mesh of the second filter. Providing that this water is not taken from the surface of the water flowing through the silt collection chamber then that water will not generally contain much fine floatable material.
The bypass means may comprise an annular passage defined radially between a downwardly directed skirt on the second filter, and the outer surface of the upper end of the outlet.
Thus when the second filter is of domed shape, the dome preferably carries a depending unapertured skirt.
The first and second filters are preferably removable from the housing for cleaning purposes, and indeed the housing itself is preferably easily removable simply by unplugging the outlet from the residual portion of downpipe left in the ground, to enable silt and debris to be cleaned from the collection chamber.
The outlet is preferably positioned eccentric to the housing outer walls to enable the axis of the housing to be adjusted horizontally in position for accommodating any misalignments of the axis of the downpipe and the axis of the upper end of the underground pipework with which the outlet is to connect.
A second aspect of the invention comprises a downpipe and underground pipework installation in which a rainwater filter assembly in accordance with the first aspect of the invention has been fitted so as to receive rainwater from the downpipe and to filter the water before it passes to the underground pipework
According to a third aspect of the invention a rainwater gully comprises a housing for positioning above ground level, said housing comprising an inlet, a housing upper end and a downwardly projecting tubular outlet, said inlet extending substantially across the full width of the upper end of the housing for receiving rainwater discharging from a downpipe, the downwardly projecting tubular outlet being couplable with a substantially vertical pipe extending below ground level, and said outlet being positioned eccentric to said housing upper end.
We are aware from searches of the existence of specification no. GB 2327453A entitled xe2x80x98Liquid re-channelling devicexe2x80x99. Although the structure of that device has a superficial resemblance to that of the applicant""s invention, the re-channelling device comprises a pipe attachment means for connecting a re-channelling pipe to the housing. The present invention is not concerned with the provision of a pipe attachment means.